Various downhole applications benefit from or rely upon the detection of the presence of a particular material, such as a fluid, in a wellbore. Based upon such detection, surface operators are then able to take further actions, such as introducing a new fluid, ceasing injection of a fluid, and the like. Downhole detection techniques typically call for specialized telemetry such as electromagnetic pulses and fiber optics for communication with surface operators. In addition, operators can employ tracers to detect particular fluids, volumes, and flow rates. Hence, while accurate downhole fluid detection is important, especially for offshore operations, existing techniques such as those described above add complexity and equipment demands.